An ignition coil for an engine, such as, an internal combustion engine, is equipped with, for example, a primary coil and a secondary coil arranged concentrically stacked on an inner periphery and outer periphery, a center core arranged at an axial centered position of the primary coil and the secondary coil, and an outer core positioned on an outer peripheral-side of the primary coil and the secondary coil (patent literature 1). Each of the configuring elements are accommodated inside a case. A resin filler made of a thermosetting resin, for example, epoxy resin fills in gaps formed inside the case. The resin filler is used to fill the gaps inside the case and insulate the configuring elements.
At a manufacturing stage of the ignition coil, after the configuring elements, for example, the primary coil, the secondary coil, center core and the outer core are mounted inside the case, and a fluid resin filler, poured inside the case from an opening port of thereof, is solidified.